Nanogranular thin film and magnetic recording media

Abstract

A nanogranular thin film consisting of nonmagnetic matrix and ferromagnetic fine particles in nano scale is improved to enhance the thermal stability and the S/N ratio. The ferromagnetic fine particles consist of (FeaCo1-a)1-xPtx, (0.3<=x<=0.7, 0.1<=a<=1), (FeaCo1-a)1-xPdx, (0.3<=x<=0.7, 0.1<=a<=1) or (FeaCo1-a) 1-x(PtbPd1-b)x, (0.3<=x<=0.7, 0.1<=a<=1, and 0<b<1).

What is claimed is:  
     
       1. A nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 70 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic fine particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x Pt x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1. 
     
     
       2. A nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 70 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic fine particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x Pd x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1. 
     
     
       3. A nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 60 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic fine particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x (Pt b Pd 1-b ) x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1, and 0<b<1. 
     
     
       4. A magnetic recording media comprising a nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 70 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic fine particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x Pt x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1. 
     
     
       5. A magnetic recording media comprising a nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 70 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x Pd x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1. 
     
     
       6. A magnetic recording media consisting of a nanogranular thin film having 160 kA/m of coercive force and consisting of from 40 to 70 atomic % of a nonmagnetic matrix and from 60 to 30 atomic % of ferromagnetic particles having 20 nm or less of average particle size, being distributed in the nonmagnetic matrix, and being expressed by a general formula (Fe a Co 1-a ) 1-x (Pt b Pd 1-b ) x , with the atomic composition ratio of 0.3≦x≦0.7, 0.1≦a≦1, and 0<b<1.